What color was US Army artillery, wagons, and mechanized equipment in the colonial, just before WWI era?

I have heard it was gloss dark gray, with black trim. Is that correct? One of the items I am looking to paint is a collection of US Army or civilian tanks made just before the US Army was sending significant numbers of troops to Europe in WWI. I am also looking to paint large, horse or tractor drawn artillery for the same general era.

My plan is to build models of American vehicles the USA sometime in the 15 years before actual US involvement in WWI.

I would like to thank all of you for your help in this project. The project continues but I have made some progress. My goal is to depict a mythical US Army National Guard unit sometime between about 1895 to just before American involvement in WWI, so about 1916/1917.

I am using mostly 1/72nd scale figures and vehicles, with a few other non-scale models tossed in. These are slush cast artillery toys made in the 1930s, and 1940's. They came from eBay and were totally thrashed when I got them, dented, very little paint, many were mis-molded. I stripped the paint off and repaired or replaced various parts and then repainted them using some of the guidance I got from this group and others. They are not expected to be 100% accurate, but I think they look nice and are fun.

Despite the sign marking Charlie Crenshaws old US 6 inch howitzer in South Carolina, these defiantly did not go overseas in WW1.The only US designed piece to see overseas service in WW1 is the US 4.7 inch M1906 fieldgun.See this link:

US Field Artillery was painted olive green with black gun tubes and wheel hubs from the 1860s through the 1890s.Sometime after that some pieces were painted grey and apparently in some cases olive/tan.With WW1, Olive Drab was the most commonly used paint but the US Army Three Color Camouflage was also introduced and used on almost all types of ordnance and vehicles in the late WWI era.See my French 75mm mle/97 for an example:

Also, in the page on my US M1918 Limber you can see the factory color plate for the M1918 Caisson in 3 color cammo, plus the photos of the cammo being applied in the factory before overseas shippment --- also see the "See Period Photos" link at the top of this page :

The October 1918 US Army Ordnance Department publication â€śPainting Instruction for Camouflaging of Ordnance Vehiclesâ€ť stated that â€śPrior to 1914 the only attempt to lessen visibility was by painting the vehicle with a monotone, battleship gray or olive drab.â€ť The 1906 US War Department Circular 66 specified the use of Olive Drab for army wagons and indicated that this color could be mixed using 6 pounds White Lead in Linseed Oil, 1 pound Raw Umber pigment, 1 pint Turpentine, and Â˝ pint Japan Drier. Surviving samples show it to be lighter that World War II Olive Drab. This color remained standard through World War I, and was authorized in the annual editions of the â€śManual for Quartermaster Corps, United States Armyâ€ť through 1917.